what a load of waffle.
It wasn't some spotty "sales associate" was it?
Essentially removing the region code management (or making it multi region in lamens terms) does not affect laser life whatsoever!!!
All you are doing, is allowing for the machine to playback original dvd titles that are from a region other than what the machine was intended to play! You are not asking the laser to work any harder...
This person doesn't know what they're talkign about. Now if they'd said something along the lines that if your player doesn't playback cd-r and you manage to find some that work, this may shorten the life expectancy of the laser, then they'd be right.
However one thing to note. For some bizzare reason a lot of Sony dvd players, particularly the X3X (735,535 etc.) series including the DAV-S300, tended to have a laser life span of approx. 14 months. Many a time I have wondered is there an internal timer that goes bang after x months playback???
Anyway, within 18 months of purchase dvd technology has progressed so far and disc content becomes so complicated that you need to upgrade anyway...so what does it really matter...